1. Field of the Invention
This invention relates to a telephone apparatus which includes a plurality of extension telephone sets capable of making an extension-to-extension telephone call and also to a telephone calling method for a telephone apparatus of the type mentioned.
2. Description of the Prior Art
Telephone apparatus which include a plurality of extension telephone sets capable of making an extension-to-extension telephone call such as, for example, cordless telephone systems is already known and in practical use. In a telephone apparatus of such type, when a base unit is to be rung from a portable unit or reversely when a portable unit is to be rung from the base unit, an intercommunication ringing signal is transmitted on radio waves from the calling side, and an audible ringing signal generating circuit is activated on the called side in response to reception of the radio waves to develop an audible ringing signal such as a buzzer sound or an audible dial tone to give information of such telephone call.
In telephone apparatus which include a plurality of extension telephone sets capable of making an extension-to-extension telephone call including such cordless telephone sets as described above, it is a common practice to call a called telephone set using an audible ringing signal such as a buzzer sound or an audible dial tone as described above. Accordingly, with conventional telephone apparatus, even if a telephone call is had, it cannot be discriminated to whom the telephone call is directed, and therefore, a person nearest to the rung telephone set is obliged to take and relay the telephone to a person called by the telephone call.